Manhole risers, manhole chimneys, all generically describe the top of the unit which extends from sewer pipes to the ground surface. In particular, the top portion of the manhole riser comprises numerous cement adjusting rings, which sit atop each other and typically have specific dimensions. Each ring may be added to increase the height that the manhole riser extends to. As a road is repaved and new layers of pavement are added, it often times is necessary to add an additional ring such that the manhole covers stay flush with the road.
Catch basins are situated below storm sewer drainage grates found on roads. The storm sewer grates are collection sites for water drainage from streets which flow through catch basins. Catch basins generally comprise a series of rectangular cement rails or collars. The cement collars are stacked in a manner to create a rectangular "basin" through which water passes. Each collar of the basin generally comprises two three-sided cement rails which, when fitted together, create a rectangle. The catch basins extend up to the grate, through which drainage water passes.
A problem that has existed with manhole risers and catch basins in the past is surface and interior water or gasses pass through gaps and spaces in the cement rings and cement collars. Further, the water will often times freeze between and within the cement structures, and the freeze/thaw cycle will deteriorate and break up the cement structures, requiring them to be replaced.
Installation, repair or replacement of sanitary/storm manhole risers, storm catch basins, and storm sewer pipes is a continuous process in maintaining the infrastructure of municipalities. In this process, a special skill called "adjustment" or "adjusting" occurs. Adjustment/adjusting is a process whereby the manhole riser or storm catch basin is adjusted to the height of the road surface.
As water utilities are installed, a manhole for access to the infrastructure system is constructed according to engineering plans on a straight line. If the road has a curve, it requires more manholes than a straight road. The bottom section of the manhole utility access is called a barrel, and between the barrel and riser is the "cone". The cone is made of pre-cast concrete and will not leak because it is one piece. After the cone is placed in position, the adjustment process begins at the top of the cone in order to cause the manhole riser necking to meet flush with the road surface. By using concrete adjusting rings and mixed Portland cement on top of the cone, rings are stacked to bring the manhole and top casting to the road elevation. The procedure is similar for storm catch basins.
Poor workmanship, poor cement, improper grouting, and the freeze/thaw cycle will cause hairline cracks in the adjustment necking. If a crack develops in the asphalt, water seeks its lowest level and begins to work against the cracks. Soon thereafter, the cracks enlarge and water, dirt and other debris begin to seep into the infrastructure.
A further problem occurs at the road surface around manhole risers and catch basins. When leaks develop, the soil erodes, and the erosion causes the ground to sink. This ground sinking action then causes the catch basin or manholes to protrude, and the road needs to be repaired. This loss of supporting material causes the road to collapse around the resultant voids.
Previously, contractors practicing the adjusting process for utilities and municipalities have not had an economical solution for the above problems. One solution, a "filter blanket", has been used in the past. The filter blanket is a geo-textile fabric material that is placed on new roads that have poor underlying soils. The filter blanket gives strength to the road surface. Often times, a contractor will simply cut off a piece of the filter blanket and wrap around the manhole neck to help prevent sand and dirt from passing into the manhole. However, the filter blanket is not adequate for the prevention of water to pass into the adjustment rings.
Additional problems result from water and gas attacking the structures from the inside. For a variety of reasons, water and other liquids attack the interior of the rings and the cement which secure the rings and casting. Sewer gasses such as hydrogen sulfide are particularly corrosive, thus there is a need for an inner seal as well.
These problems are described in U.S. Pat. Nos. 4,475,845 and 4,469,467. These patents describe the problems of water infiltration into manhole chimney seals, and attempt to provide a solution. However, the problem with the solutions proposed in the '845 and '467 patents has not been satisfactory to date, due to the high cost of the product. The '845 patent discloses a chimney seal having numerous sealing sections and a securing means for the chimney seal. In particular, the sealing means describes a retaining band to be used with different preformed skirts. The '467 patent discloses a similar apparatus. The products allegedly covered by these patents are very expensive, and not feasible for widespread use as manhole riser sealer systems. Due to the numerous numbers of manholes which exist and the increasingly tight budgets of municipalities, there exists a need for an inexpensive apparatus and method of sealing, which does not employ the use of "preformed" rings.
U.S. Pat. Nos. 4,540,310, 4,737,220 and Canadian Patent No. 1,142,009 all claim to have some type of sealing means which could be used for sealing water from manhole risers. However, none of these patents address the problems associated with a need for a low cost product and a method for sealing. The present invention addresses such a need, and is disclosed herein. Further, the above patents and existing solutions are directed to manhole risers, and do not address the needs addressed in the catch basin market.
It is the object of this invention to create a barrier which may be placed over adjustment necks of manhole risers and catch basins in a manner of minutes with a one person operation.
It is the object of this invention to have an economical, cost effective method, in dealing with water leaks and deterioration of adjustment necks and catch basins. The present invention eliminates contaminated water, sand, dirt and other debris from penetrating into water system infrastructures, and thereby eliminates or reduces the amount of water treatment needed at the city water treatment plant.
It is the object of this invention to provide an economical method of sealing the intersection between two adjoining pipes.
It is the object of this invention to provide an inner seal for manhole risers and catch basins such that cracks and leakage do not occur from the inside due to exposure to sewer water and gasses.
The present invention also reduces the amount of ground erosion associated with cracks and leakage caused by cracks in manhole risers and catch basins.